What safety precaution should maintenance personnel follow when moving a propeller by hand?

What safety precaution should maintenance personnel follow when moving a propeller by hand?

• A. Verify the magneto switch is off and stay clear of the propeller arc.
• B. Leave the ignition switch ON to test responsiveness.
• C. Stand in the propeller arc to observe movement.
• D. Disconnect the battery and turn off the master switch.

Answer: (A)

When you move a propeller by hand, the risk is that the engine could fire or a blade could strike you. The most direct safety step is to disable the ignition so no spark can occur if the prop starts to move. Turning the magneto switch off stops ignition energy from the spark plugs, which is essential even if the engine isn’t running. At the same time, you must stay out of the propeller arc because a blade can move suddenly or be driven by wind, delivering a severe injury. Leaving the ignition on would reintroduce the risk of ignition, and standing in the arc eliminates the most basic protection against contact with a moving blade. Disconnecting the battery or turning off the master switch can add safety, but the key precaution for preventing ignition while handling the prop is having the magnetos off and keeping clear of the arc.

When you move a propeller by hand, the risk is that the engine could fire or a blade could strike you. The most direct safety step is to disable the ignition so no spark can occur if the prop starts to move. Turning the magneto switch off stops ignition energy from the spark plugs, which is essential even if the engine isn’t running. At the same time, you must stay out of the propeller arc because a blade can move suddenly or be driven by wind, delivering a severe injury. Leaving the ignition on would reintroduce the risk of ignition, and standing in the arc eliminates the most basic protection against contact with a moving blade. Disconnecting the battery or turning off the master switch can add safety, but the key precaution for preventing ignition while handling the prop is having the magnetos off and keeping clear of the arc.